Alt text, short for alternative text, is a simple but powerful way to make your online course more accessible for all your students. Alt text is a written description of an image, infographic, or diagram that convey what is being shown on screen. Screen readers read it aloud, and it shows up in place of the image if it doesn’t load. Beyond accessibility laws like the ADA or Section 508, alt text supports equity. It helps students learning in low-bandwidth environments or using alternative formats engage with your content. Most importantly, it’s a way to respect your students’ varied needs and life realities.
In this guide, you’ll learn what good alt text looks like, how to use AI to write it, and how to review and revise what AI suggests. When you use AI to support the process, it becomes fast, easy, and scalable.
What Makes Alt Text Effective?
Effective alt text is short, specific, and relevant to the purpose of the image. It doesn’t just describe what the image looks like, it explains what it means in the context of your course. For example, a diagram showing a five-step writing process shouldn’t just say “Diagram with five arrows.” Instead, it might read “Five-step writing process from prewriting to publishing” and include each of the steps with a description.
If the picture is purely decorative you can mark it as decorative, and if you’ve fully explained the image in the nearby text or caption, a short, functional description may be all that’s needed. Alt text should complement, not duplicate, what’s already there.
Writing Alt Text with AI
AI can help you get started with alt text quickly. Think of it like a helpful assistant who can generate first drafts while you focus on teaching. Tools like ChatGPT, Copilot, and Gemini can describe images accurately and adapt to different tones or learning goals. But remember, you’re still the expert on your students and your course. That means you’ll want to review and clarify what AI suggests. When using AI, give it context. Tell it who the audience is (college students), what course the image is in, and what the image is supposed to teach. The more context you provide, the better your results will be.
Select your AI Tool
You can use many tools to help you write and manage alt text. Some LMS platforms have built-in accessibility checkers that flag missing alt text, making it easy to identify which images you need to update. Upload your image into your preferred AI tool (ChatGPT Alt Text Guru, Claude, Copilot, or Gemini) and use one of the prompts below. You can also check out Arizona State University’s web-based Alt text generator if you’re in a rush.
Use Prompts That Match Your Image Type
Let’s walk through a few examples based on common visuals used in online, accelerated courses.
You are a subject matter expert in [course name/topic] writing alt text for course materials. Detail the [ title with short description ] in under 125 characters, including its instructional purpose. Highlight key takeaways. [Insert image or description here].
You are a subject matter expert in [course name/topic] writing alt text for course materials. Describe the [ title with short description ] in under 125 characters, including its instructional purpose. Highlight key processes. [Insert image or description here].
You are a subject matter expert in [course name/topic] writing alt text for course materials. Detail the [ title with short description ] in under 125 characters, including its instructional purpose. Highlight key connections in the graphic. [Insert image or description here].
You are a subject matter expert in [course name/topic] writing alt text for course materials. Write alt text for the [ title with short description ] in under 125 characters, including its instructional purpose as it relates to [topic]. [Insert image or description here].
Once you have the output, review it to make sure it says what you need. A good workflow is to upload your image, use AI to generate a draft, review it for accuracy, then paste it into your image settings or alt text field in the platform you’re using. Be sure to double-check before publishing.
